New Delhi: The Congress today unholstered a biting attack on Narendra Modi for the alleged illegal monitoring of a young woman in his state in 2009 by senior police officials. The Congress has alleged that Mr Modi, who is running for Prime Minister, authorised police officials via his then Home Minister, Amit Shah, to tap the woman architect's phones and follow her.

The audio tapes were given to the CBI by a senior Gujarat police officer, GL Singhal, who has allegedly said that more than 200 of the recorded conversations are between him and Mr Shah. The CBI has not taken voice samples from either man to confirm if the voices on the tape are indeed theirs.

Mr Singhal has reportedly divulged to the CBI that senior members of Gujarat's anti-terror squad were among those assigned to tail the woman whose identity must be protected for legal reasons.